This invention relates to a process and apparatus for the production of calcium chloride by the reaction of hydrochloric acid and calcium carbonate.
It is well known that an aqueous calcium chloride solution can be produced by the neutralization of aqueous hydrochloric acid with calcium carbonate. After process initiation, the produced calcium chloride containing aqueous solution is withdrawn from the reaction vessel and a portion thereof is recycled to an absorption tower into which is also fed hydrochloric acid and water. The resultant aqueous hydrochloric acid-calcium chloride solution is then fed to the neutralization reaction to provide the hydrochloric acid reactant. The aqueous calcium chloride solution fed to the absorber contains fines and must be first clarified, such as by filtration, so as to prevent pluggage of the recycle line and absorber. These fines may comprise bits of unreacted calcium carbonate and inerts which are associated with the calcium carbonate feed. If the calcium carbonate is provided by limestone, these inerts are usually silts which coexist with the limestone at the quarry. Since the concentration of fines can be considerable, the filters used must be frequently cleaned or replaced. This necessitates interruption of process operation and adds to the cost of the process.
It is therefore an object of this invention to provide a process for the production of an aqueous calcium chloride solution by the reaction of aqueous hydrochloric acid with calcium carbonate, which process removes fines from the aqueous calcium chloride solution without the use of a filter.